This application relates to a selector valve for selecting between two pressure sources to be delivered to a downstream use, wherein the selector valve has positions at which it delivers solely from each of the two sources, but has an intermediate position at which it mixes the two sources to be delivered to the use.
Selector valves are known, and are typically utilized to supply a fluid from alternate sources to a downstream use. In one proposed application, two distinct oil pumps deliver oil to the selector valve. The selector valve selects between the two oil supplies, and delivers the oil to a downstream use. In one application this downstream use is a gear box for a geared architecture gas turbine engine.
The purpose of this selector valve is to ensure that adequate oil is supplied. Thus, there is a primary oil pump that will typically be delivered through the selector valve to the gear box. However, if the pressure of this primary oil pump drops below a predetermined level, the selector valve will move toward another position at which it will deliver oil from a secondary oil pump.
Selector valves such as mentioned above typically toggle or snap between the two extreme positions. Thus, they tend to oscillate between the two positions, creating unwanted noise, and a non-smooth operation.